The need for energy absorbing padding to cushion mechanical impact loads is present in many environments. For example, personal protection equipment such as helmets, shin guards and body part protectors typically include some form of cushioning layer. The type of helmet commonly used in football, for example, has a hard outer shell that generally is molded of impact resistant plastic such as acrylonitrile butadiene styrene (ABS) or polycarbonate. The interior of the helmet is lined with various components that may be formed, for example, from various materials such as felt, fibrous knits, foam-padding material such as ethylene vinyl acetate, vinyl nitrile or urethane/rubber. The liner is included in the design of the helmet and functions to provide some cushioning of direct physical impacts during active play.
Other environments where high impact forces are present are those involving body armor. For example, bulletproof vests typically are fabricated from polyaramid (Kevlar®), polyolefin fibers, woven or mat fabrics having high impact and cut resistance. When struck by a projectile, these vests and similar clothing can impress a direct force on the wearer's body area that, while potentially life-saving, can cause significant bodily bruising and/or a bone fracturing injury.
It is desirable in these and in other environments where impact forces are involved that the helmet or protective garment be comfortable and in some applications, that it has the ability to allow airflow between the user's body and the helmet or protective garment. It also would be desirable to provide a liner construction adapted for use in such environments that is flexible, can be formed in various shapes, displays an energy absorbing compression function, can be worn close to the body and may enable airflow between the body and the protective helmet or garment.